Radiator cap not working? - Pressure in coolant 24 hrs after running engine

[sebastian323]

On my 1996 4.0 OHV I recently thought I saw some coolant on my driveway (green looking oily liquid). The truck was parked on an incline for 2 weeks with the nose of the truck facing forward. And the coolant seemed to be dripping from the back of the engine. I moved the truck and parked it on flat ground and did not see any leaks after 24hrs. However, when I opened the radiator cap, the coolant was under slight pressure and some poured out, 24 hours after the engine was last run. The overflow tank was also more or less empty.

As far as I know the only hoses in the cooling system are from the engine to/from the radiator and from the engine to the heater core ( looks like a single hose ??). Does the throttle receive coolant as well ?

According to all data the specification for the radiator cap is 18 psi for 1995-1996 rangers and 16 psi for 1993-1994

 

[alwaysFlOoReD]

There is also a hose to the overflow tank. No other I'm aware of on motors I've worked on; 4.0 and 2.9
Sounds like you have a leak somewhere.
Tho there shouldn't be pressure in the system after sitting either. Rad cap is cheap. Change it.